{"id":"CVE-2025-40246","summary":"xfs: fix out of bounds memory read error in symlink repair","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfs: fix out of bounds memory read error in symlink repair\n\nxfs/286 produced this report on my test fleet:\n\n ==================================================================\n BUG: KFENCE: out-of-bounds read in memcpy_orig+0x54/0x110\n\n Out-of-bounds read at 0xffff88843fe9e038 (184B right of kfence-#184):\n  memcpy_orig+0x54/0x110\n  xrep_symlink_salvage_inline+0xb3/0xf0 [xfs]\n  xrep_symlink_salvage+0x100/0x110 [xfs]\n  xrep_symlink+0x2e/0x80 [xfs]\n  xrep_attempt+0x61/0x1f0 [xfs]\n  xfs_scrub_metadata+0x34f/0x5c0 [xfs]\n  xfs_ioc_scrubv_metadata+0x387/0x560 [xfs]\n  xfs_file_ioctl+0xe23/0x10e0 [xfs]\n  __x64_sys_ioctl+0x76/0xc0\n  do_syscall_64+0x4e/0x1e0\n  entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n kfence-#184: 0xffff88843fe9df80-0xffff88843fe9dfea, size=107, cache=kmalloc-128\n\n allocated by task 3470 on cpu 1 at 263329.131592s (192823.508886s ago):\n  xfs_init_local_fork+0x79/0xe0 [xfs]\n  xfs_iformat_local+0xa4/0x170 [xfs]\n  xfs_iformat_data_fork+0x148/0x180 [xfs]\n  xfs_inode_from_disk+0x2cd/0x480 [xfs]\n  xfs_iget+0x450/0xd60 [xfs]\n  xfs_bulkstat_one_int+0x6b/0x510 [xfs]\n  xfs_bulkstat_iwalk+0x1e/0x30 [xfs]\n  xfs_iwalk_ag_recs+0xdf/0x150 [xfs]\n  xfs_iwalk_run_callbacks+0xb9/0x190 [xfs]\n  xfs_iwalk_ag+0x1dc/0x2f0 [xfs]\n  xfs_iwalk_args.constprop.0+0x6a/0x120 [xfs]\n  xfs_iwalk+0xa4/0xd0 [xfs]\n  xfs_bulkstat+0xfa/0x170 [xfs]\n  xfs_ioc_fsbulkstat.isra.0+0x13a/0x230 [xfs]\n  xfs_file_ioctl+0xbf2/0x10e0 [xfs]\n  __x64_sys_ioctl+0x76/0xc0\n  do_syscall_64+0x4e/0x1e0\n  entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n CPU: 1 UID: 0 PID: 1300113 Comm: xfs_scrub Not tainted 6.18.0-rc4-djwx #rc4 PREEMPT(lazy)  3d744dd94e92690f00a04398d2bd8631dcef1954\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-4.module+el8.8.0+21164+ed375313 04/01/2014\n ==================================================================\n\nOn further analysis, I realized that the second parameter to min() is\nnot correct.  xfs_ifork::if_bytes is the size of the xfs_ifork::if_data\nbuffer.  if_bytes can be smaller than the data fork size because:\n\n(a) the forkoff code tries to keep the data area as large as possible\n(b) for symbolic links, if_bytes is the ondisk file size + 1\n(c) forkoff is always a multiple of 8.\n\nCase in point: for a single-byte symlink target, forkoff will be\n8 but the buffer will only be 2 bytes long.\n\nIn other words, the logic here is wrong and we walk off the end of the\nincore buffer.  Fix that.","modified":"2026-05-15T04:13:47.959008261Z","published":"2025-12-04T16:08:09.751Z","related":["SUSE-SU-2026:20207-1","SUSE-SU-2026:20220-1","SUSE-SU-2026:20228-1","openSUSE-SU-2026:20145-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40246.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/678e1cc2f482e0985a0613ab4a5bf89c497e5acc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7c2d68e091584149fe89bcbaf9b99b3162d46ee7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/81a8685cac4bf081c93a7df591644f4f80240bb9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40246.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40246"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.10.0"},{"fixed":"6.12.60"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.17.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-40246.json"}}],"schema_version":"1.7.5"}